Dialog in the RAILTEL telephone-based system

Dialog management is of particular importance in telephone-based services. In this paper we describe our recent activities in dialog management and natural language generation in the LIMSI RAILTEL system for access to rail travel information. The aim of LEMLAP project RAILTEL was to assess the capabilities of spoken language technology for interactive telephone information services. Because all interaction is over the telephone, oral dialog management and response generation are very important aspects of the overall system design and usability. Each dialog is analysed to determine the source of any errors (speech recognition, understanding, information retreival, processing or dialog management). An analysis is provided for 100 dialogs taken from the RAILTEL field trials with naive subjects accessing timetable information